ninjette.org - View Single Post - Choke raises revs to 2k RPM, then bike begins to stall.

clakmurrick · March 10th, 2021, 03:11 PM

Hey all, I'm looking for some help with the choke on my bike. Full disclaimer, I have some problems with the bike, and I'm going through any problems to limit them. I made a post previously about the problems I'm having, specifically lower RPM problems, because I modded the bike under the advice of a fellow bike enthusiast. I can't return it to stock at the moment since the airbox was broken. I have converted to velocity stacks, a jet kit, washer on the needle, and an exhaust. I can provide more details later.

Anyways, the bike never really needs the choke to start. I usually get away with cranking it while cold, and it starts. It usually has a pretty low RPM (like 800 RPM) until I give it some throttle and let it warm up, and then it usually stays where I set the idle (about 1300 RPM). The temperature around here is 65-70 F, and we're about 400 feet above sea level, so not high altitude.

When I do try and use the choke, the bike still starts, but the behavior is odd. If the bike is idling, but still cold, and I apply choke, the RPMs usually raise to about 2000 RPM for a second or two, then the bike begins to stall and will die unless I turn the choke off. I understand that the choke on the Ninja is really just an enrichener since it adds fuel, but I'm not sure why the bike decides to stall. My hypothesis is that perhaps one cylinder is getting fuel, trying to raise the RPM, but the other cylinder is not (perhaps it's clogged), so the engine is upset since there is an imbalance.

Any help is appreciated. I tried my best to clean the carbs. I've had the carbs apart 3 times to clean them, each time letting them sit in carb cleaner for hours, using needles to clean passageways. I must be missing something.

March 10th, 2021, 03:11 PM	#1
clakmurrick carb newbie Name: Clark Location: Dallas, Texas Join Date: Nov 2020 Motorcycle(s): 2008 Ninja 250R Posts: 22	Choke raises revs to 2k RPM, then bike begins to stall. Hey all, I'm looking for some help with the choke on my bike. Full disclaimer, I have some problems with the bike, and I'm going through any problems to limit them. I made a post previously about the problems I'm having, specifically lower RPM problems, because I modded the bike under the advice of a fellow bike enthusiast. I can't return it to stock at the moment since the airbox was broken. I have converted to velocity stacks, a jet kit, washer on the needle, and an exhaust. I can provide more details later. Anyways, the bike never really needs the choke to start. I usually get away with cranking it while cold, and it starts. It usually has a pretty low RPM (like 800 RPM) until I give it some throttle and let it warm up, and then it usually stays where I set the idle (about 1300 RPM). The temperature around here is 65-70 F, and we're about 400 feet above sea level, so not high altitude. When I do try and use the choke, the bike still starts, but the behavior is odd. If the bike is idling, but still cold, and I apply choke, the RPMs usually raise to about 2000 RPM for a second or two, then the bike begins to stall and will die unless I turn the choke off. I understand that the choke on the Ninja is really just an enrichener since it adds fuel, but I'm not sure why the bike decides to stall. My hypothesis is that perhaps one cylinder is getting fuel, trying to raise the RPM, but the other cylinder is not (perhaps it's clogged), so the engine is upset since there is an imbalance. Any help is appreciated. I tried my best to clean the carbs. I've had the carbs apart 3 times to clean them, each time letting them sit in carb cleaner for hours, using needles to clean passageways. I must be missing something.